The earnings season for the energy industry kicks off Wednesday when the Houston pipeline company Kinder Morgan reports its second quarter results after the market closes. Schlumberger, the oil field services giant based in Houston, Paris and The Hague, will announce earnings on Friday; Houston-based services company Halliburton announces on Monday.

Analysts are cautiously optimistic that earrings reported over the next few weeks will show that the industry's recovery advanced in the three months between April and June. At the same time, there is increasing nervousness about unstable oil prices that have remained lower than anyone expected.

"Everybody is cranking as hard as this can, but the issue is how long does the activity momentum we've seen this year last," Herbert said. Here are some things to look for this earnings season:

Exploration and production companies. These firms are the bellwethers. While pipeline business remains relatively stable, the health of services companies depends on the production companies trying to generate profits with crude prices about $10 a barrel lower than many forecasters expected.

Revenues. Many companies locked in prices above $50 a barrel with long-term contracts, so the full impact to the slide in prices may not be reflected in these earnings reports. Still, if companies are offsetting lower prices by pumping more oil, that may support the "lower for longer" outlook.

Profits. Companies have made money despite low prices by becoming more efficient and squeezing costs. But with activity picking up, particularly in the Permian Basin in West Texas, and services companies and other suppliers raising prices, the question is whether companies are finding ways to keep those costs from eating into profits.

It all comes down to oil prices. The big oil and gas companies have pushed ahead even as prices fell below $45 a barrel. But small, privately held companies are signalling a slowdown ahead unless prices recover. Will the big companies issue similar warnings?